Rotatable assembly including a coupling interface

Abstract

A rotatable assembly, such as a crankshaft or camshaft assembly, includes a first rotatable component and a second rotatable component coupled to the first rotatable component. The first rotatable component includes a first body and defines a plurality of recesses extending into the first body. The second rotatable component includes a second body and defines a plurality of protrusions extending from the second body. The protrusions are disposed inside the respective recesses to allow the second rotatable component to rotate in unison with the first rotatable component.

The invention claimed is: 
     
       1. A rotatable assembly, comprising:
 a first rotatable component including a first body and defining a plurality of recesses extending into the first body; 
 a second rotatable component including a second body and defining a plurality of protrusions extending from the second body, wherein the protrusions are disposed inside the recesses such as to allow the second rotatable component to rotate in unison with the first rotatable component; and 
 wherein the recesses are not equally spaced from one another, and the protrusions not equally spaced from one another such that the first rotatable component and the second rotatable component are configured to be assembled together in only a single orientation relative to each other, the recesses include a first recess, a second recess, and a third recess, and the protrusions include a first protrusion, a second protrusion, and a third protrusion, a first angle is defined from the first recess to the second recess, a second angle is defined from the second recess to third recess, a third angle is defined from the third recess to the first recess, the first angle, the second angle, and the third angle are all be different from each other, the first rotatable component extends along a longitudinal axis, and each of the recesses has a recess width and a tapered configuration such that the recess width of each of the recesses continuously decreases in an axial direction, the recess width of each of the recesses decreases exponentially in the axial direction, each of the recesses has a recess height, and the recess height of each of the recesses decreases exponentially in the axial direction, each of the protrusions has a protrusion width and a tapered configuration such that the protrusion width continuously decreases in the axial direction, the protrusion width of each of the protrusions decreases exponentially in the axial direction, and each of the protrusions has a protrusion height that decreases exponentially in the axial direction. 
 
     
     
       2. The rotatable assembly of  claim 1 , wherein the plurality of protrusions defines a coupling interface, and the coupling interface does not allow relative rotation between the first rotatable component and the second rotatable component across the coupling interface. 
     
     
       3. The rotatable assembly of  claim 1 , wherein each of the plurality of protrusions is in tapered, conformal contact with the plurality of recesses to create a joint with minimized runout of the second rotatable component from the first rotatable component. 
     
     
       4. The rotatable assembly of  claim 3 , wherein the tapered, conformal contact creates a unique lateral final resting position when the second rotatable component is slid onto the first rotatable component. 
     
     
       5. The rotatable assembly of  claim 1 , wherein the recesses and protrusions define a coupling interface to allow torque transmission between the first rotatable component and the second rotatable component. 
     
     
       6. The rotatable assembly of  claim 5 , wherein the torque transmission does not require a clamp load. 
     
     
       7. The rotatable assembly of  claim 1 , wherein a radius and form of the protrusions and recesses are configured to limit contact stress. 
     
     
       8. The rotatable assembly of  claim 1 , wherein each of the protrusions mates with each of the recesses such that first rotatable component is prevented from rotating relative to the second rotatable component while allowing the second rotatable component to be slid over the first rotatable component.